Vulnerability MediumRUSTSEC-2026-0045 · aws-lc-sys
RUSTSEC-2026-0045: Timing Side-Channel in AES-CCM Tag Verification in AWS-LC
Short answerA security vulnerability in the aws-lc-sys crate: Timing Side-Channel in AES-CCM Tag Verification in AWS-LC. Medium severity (CVSS 5.9). Fixed in 0.38.0: update to a fixed version.
| Crate | aws-lc-sys |
|---|---|
| Type | Vulnerability (crypto-failure) |
| Affected versions | From 0.14.0 before 0.38.0. |
| Fixed in | 0.38.0 |
| Severity | Medium, CVSS 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N |
| Published | 2026-03-02 |
| Last changed | 2026-03-21 |
| Also known as | CVE-2026-3337, GHSA-65p9-r9h6-22vj, GHSA-frmv-5gcm-jwxh, RUSTSEC-2026-0043 |
What to do
- See which version you have:
cargo tree -i aws-lc-sys(it also shows which of your dependencies pulls it in). - Update within your version requirement:
cargo update -p aws-lc-sys. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for exampleaws-lc-sys = "0.38.0") or update the dependency that pulls it in. - Check again with
cargo audit, or paste your Cargo.lock into our Cargo.toml checker.
Details from the advisory
Observable timing discrepancy in AES-CCM decryption in AWS-LC allows an unauthenticated user to potentially determine authentication tag validity via timing analysis.
The impacted implementations are through the EVP CIPHER API: EVP_aes_128_ccm, EVP_aes_192_ccm, and EVP_aes_256_ccm.
Customers of AWS services do not need to take action. aws-lc-sys contains code from AWS-LC. Applications using aws-lc-sys should upgrade to the most recent release of aws-lc-sys.
Workarounds
In the special cases of using AES-CCM with (M=4, L=2), (M=8, L=2), or (M=16, L=2), applications can workaround this issue by using AES-CCM through the EVP AEAD API using implementations EVP_aead_aes_128_ccm_bluetooth, EVP_aead_aes_128_ccm_bluetooth_8, and EVP_aead_aes_128_ccm_matter respectively.
Otherwise, there is no workaround and applications using aws-lc-sys should upgrade to the most recent release.
References
- Package: crates.io/crates/aws-lc-sys
- Advisory: rustsec.org/advisories/RUSTSEC-2026-0045.html
- Web: aws.amazon.com/security/security-bulletins/2026-005-AWS
- Advisory: github.com/aws/aws-lc-rs/security/advisories/GHSA-65p9-r9h6-22vj
From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.
Other advisories for aws-lc-sys
- VulnerabilityRUSTSEC-2026-0044 · 2026-03-19AWS-LC X.509 Name Constraints Bypass via Wildcard/Unicode CN
- Vulnerability HighRUSTSEC-2026-0046 · 2026-03-02PKCS7_verify Certificate Chain Validation Bypass in AWS-LC
- Vulnerability HighRUSTSEC-2026-0047 · 2026-03-02PKCS7_verify Signature Validation Bypass in AWS-LC
- Vulnerability HighRUSTSEC-2026-0048 · 2026-03-19CRL Distribution Point Scope Check Logic Error in AWS-LC
Up next
Same crateaws-lc-sys: security historyEvery advisory for this crate, and whether it is safe to use today.Read it next →Did this answer your question?